Amount of energy needed to melt a solid

Click For Summary
SUMMARY

The discussion focuses on calculating the energy required to melt 25g of pure gold, starting from an initial temperature of 22 degrees Celsius. The specific heat capacity (c) of gold is 129 J/kg°C, and the latent heat of fusion (Lf) is 64,500 J/kg. The total energy (Q) needed for the process is calculated using the formula Q = mcΔT, resulting in 33,605 J, not including the latent heat of fusion. Participants emphasize the importance of indicating units in calculations for clarity.

PREREQUISITES
  • Understanding of specific heat capacity and latent heat concepts
  • Familiarity with the formula Q = mcΔT
  • Basic knowledge of thermodynamics
  • Ability to perform unit conversions and calculations
NEXT STEPS
  • Study the concept of latent heat and its applications in phase changes
  • Learn about the specific heat capacities of various materials
  • Explore advanced thermodynamic equations for energy calculations
  • Practice problems involving heat transfer and phase transitions
USEFUL FOR

This discussion is beneficial for students in physics or chemistry, educators teaching thermodynamics, and anyone interested in understanding energy calculations related to phase changes in materials.

SelenaT
Messages
12
Reaction score
0

Homework Statement


A jeweler heats 25g of pure gold until molten. If the initial temperature of the gold is 22 degrees celsius, calculate the amount of energy required for the process.

Homework Equations


c = 129
Lf= 64 500
Lv = 1578000
Tmelt = 1064

The Attempt at a Solution


Q = mct
= 0.25kg(129)(1064-22)
= 33605J
 
Physics news on Phys.org
You need to add the latent heat of fusion. The problem statement indicates that the gold in the final state is molten.

Chet
 
And please get in the habit of indicating units for the quantities used in your calculations. It is very confusing otherwise.
 

Similar threads

Replies
11
Views
5K
Replies
2
Views
2K
  • · Replies 13 ·
Replies
13
Views
4K
Replies
3
Views
3K
Replies
2
Views
8K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 16 ·
Replies
16
Views
4K
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
6K
  • · Replies 6 ·
Replies
6
Views
4K